Centering chuck



Aug. zo, 1929.

A. w. coPLAND 1,725,342

CENTERING CHUCK Filed Oct. 22, 1923 2 Sheets-Sheet 1 Patented Aug. 20,1929.

UNITED STATES PATENT OFFICE.y

ALEXANDER W. CoPLAND, or DETROIT, MICHIGAN; DETROIT AND SECURITY TRUSTCOMPANY, ADMINISTRATOR, AND HEATLEY CREEN, ExECUToR oF sAID ALEXAN- DERw. CorLAND, DECEAsED, AssIGNoR-s To sUsAN D. CorLAND, or MENING- HAM,MICHIGAN.

CENTERING CHUCK.

Application filed October 22, 1923.

It is the object of the invention to provide means for automaticallyexactly centering and holding a member having a toothed circularperiphery, such for instance as a gear or an index Wheel. To this endthe invention consists in the novel construction as hereinafter setforth.

In the drawings:

Figure l is a longitudinal section through the chuck;

Figure 2 is a cross-section on line 2 2 of Figure l;

*igure 3 is a diagram illustrating in an exaggerated manner theself-centering principle;

Figure 4 is an enlarged section of a portion of Fig. 2.

Then a spur gear is placed in engagement with a corresponding internalgear with a certain amount of clearance or backlash, it is possible forsaid gears to assume an Veccentric relation. If, however, there isimparted to these gears a relative torque stress, this will place theiraxes in coincidence. The principle involved is illustrated in Figure 3,in which 1 is a spur gear having three teeth, 2, 8 and 4, and 5 is aninternal gear having three teeth 6, 7 and 8. As shown in dotted lines,these gears can assume an eccentric relation, due to the clearancesprovided, but in that eccentric relation at least one of the teeth (4)on the spur gear is out of contact with the cooperating tooth (8) of theinternal gear. A torque stress applied to the spur gear in the directionof the arrow will bring the tooth et in contact with the tooth 8, butthis will also cause the axis of the spur gear to move into coincidencewith the axis of the internal gear. Ilierefore,- with any gear havingmore than two teeth and which 1s placed in engagement with thecomplementary gear in an internal-external relation, the application ofa torque stress will cause an automatic centering.

As shown in Figures 1 and 2, A is the rotary spindle of a lathe, or anysuitable construct-ion of internal grinding machine. B is a headthreaded for engagement with the spindle A upon which is mounted theannular head C for holding an internal gear wheel D. The teeth E of thisgear Wheel D are of the same pitch as those of the gear to be centered,but with sufficient clearance Serial No. 670,209.

to provide for easily engaging and disengaging said gear.

To apply a torque to the gear which is in engagement with the chuck, Ipreferably provide a pair of dogs on diametrically opposite sides of thechuck for engaging two of the gear teeth and for yieldably pressing thesame in opposite directions. As shown, these dogs E are in the form ofbars slidable in slots F in the gear D and having inwardly projectingfingers G for engaging the teeth of the gearto be centered. The slots Fmay, if desired, be formed by milling from the periphery of the gear Dand segmental guide blocks H are then placed in the outer portion ofthese slots to assist in guiding the bars4 E. I is a segmental leverhaving its opposite ends in engagement with the bars E and fulcrumedcentrally at J, thereby causing the bars E to move simultaneously inopposite directions. K and K are springs for yieldably pressing the barsF. to move the same longitudinally, and L is a screw bearing against oneend of the lever I for actuating the same and the connected bars E in adirection opposed to the pressure of the springs. y

lith the construction as described, to engage the gear with the chuck,the screw L is adjusted by means of a suitable wrench (not shown) so asto move the fingers G into a position where they will not obstruct theentrance of the gear to be centered such as M. This gear M is thenplaced in engagement with the internal gear D, after which the screw Lis turned in the opposite direct-ion to relieve pressure upon the leverI and to permit the springs K and K to yl'orce the fingers G against twodiametrically opposite teeth of the gear M. This will impart a torque tothe gear, which will cause the same to automatically assume a positionin exact axial coincidence with the gear D. The tension of the springs Kand K is sufficient to hold the parts in this relation during thegrinding operation, after which a reverse turning of the screw L willrelease the gear and permit of replacing the same by another gear to becentered.

While I have specifically described the use of my invention in thecentering and holding of a gear, it is obvious that it is equallyapplicable to any other member having a toothed circular periphery.

` A internal gear Wheel mounted on said head and adapted totelescopically receive the gear to be centered, dogs upon opposite sidesof said internal gear Wheel for engaging l teeth of the gear to becentered, a connection between said dogs for causing the same to move inopposite directions, a spring for yieldably forcing said dogs in onedirection, and means for relieving pressure of said spring to move thedogs in the opposite direction.

3. A centering device for a toothed circular member comprising a memberhaving a plurality of fixed teeth arranged to en j gage the teeth ofsaid irst mentioned member and having suiiicient clearance to permit theinsertion and Withdrawal of said first mentioned member, and means torplacing a relative torque pressure on said members to exactly center thesame.

4c. A centering device for a toothed cir- Y cular member comprising amember having a plurality ci' fixed teeth arranged to engage tlie teethof said first mentioned member and having sufiicient clearance to permitengagement, and means Vmovable With respect to said fixed teeth andadapted to engage said firstmentioned member to place a torque pressureon said member relative to said fixed teeth.

y 5. An automatic centering chuck for a toothed circular membercomprising a head, a. member mounted on saidl head complementary to andsustaining an internal-external relation to said toothed circularYmember with su'iicient clearance for ready engagement anddisengagement, and resilient means for applying a yielding` torque tomove one ot said members in relation to the other therebg7 exactlycentering and holding the same trom displacement.

6. A centering device for a toothed circular member comprising acomplementary member sustaining an internal-external relation theretoand having a plurality of integral spaced bearings in xed-relation toeach other lfor engagement With said toothed circular member withclearance :tor permit ting such engagement and resilient means forapplying a torque to Center and hold said members.

7. A centering device for a toothed circular member comprising acomplementary member sustaining internal-external relation thereto andhaving a plurality of teeth for engagement with the teeth oi saidtoothed circularmember and resilientmeans on the diameti'ically oppositesides of said member for applying pressure in opposite directions to theteeth of said toothed member thereby producing a torque.

In testimony whereof I ailix my signature.

ALEXANDER IV. COPLAND

